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Updated: May 1, 2026
Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration
Published on: May 19, 2023
Quantifying iron-oxide nanoparticles at high concentration based on longitudinal relaxation using a three-dimensional
Jinjin Zhang1, Ryan Chamberlain, Michael Etheridge
1Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA; School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota, USA.
This study introduces a new method using SWIFT Look-Locker to accurately measure T1 values for iron-oxide nanoparticles (IONPs) at high concentrations. This advance enables better mapping of IONP distribution for applications like magnetic nanoparticle hyperthermia therapy.
Area of Science:
- Biomedical Engineering
- Magnetic Resonance Imaging
- Nanotechnology
Background:
- Iron-oxide nanoparticles (IONPs) are valuable MRI contrast agents.
- Conventional T2* mapping struggles with high IONP concentrations due to rapid signal decay.
- High IONP concentrations are relevant for thermal therapies.
Purpose of the Study:
- To develop and validate a method for quantitative IONP mapping at high concentrations.
- To combine Sweep Imaging with Fourier Transformation (SWIFT) and the Look-Locker method for T1 mapping.
- To overcome limitations of T2* mapping in high-concentration scenarios.
Main Methods:
- T1 values of IONPs in agar were measured using SWIFT Look-Locker and inversion recovery spectroscopy.
- The precision of SWIFT Look-Locker and Variable Flip Angle (VFA) methods was compared via simulations.
- IONP concentrations up to 53.6 mM of Fe were analyzed.
Main Results:
- A linear relationship was observed between R1 (1/T1) and IONP concentration up to 53.6 mM.
- This concentration range is significantly higher than previously reported.
- Simulations indicated SWIFT Look-Locker is less sensitive to B1 inhomogeneity than VFA.
Conclusions:
- SWIFT Look-Locker accurately measures T1 for IONP concentrations up to 53.6 mM.
- This method provides a way to map IONP distribution.
- Accurate IONP mapping can aid in planning magnetic nanoparticle hyperthermia therapy.
